Adding and subtracting device



A. WOLPERT. ADDING AND SUBTRACTING DEVICE.

APPLICATION FILED DEC. 27, I920- Patented Feb 14 19220.

UNITED STATES ALBERT WOLPERT, 0F PITTSBURGH, PENNSYLV ANIA.

Specification of Letters Patent.

ADDING AND SUIBTRACTING DEVICE.

Patented Feb. 14, 1922.

Application filed December 27, 1920. Serial No. 433,145.

To all whom it may concern:

citizen of the United States,'residing at Pittsburgh, in the county ofAllegheny and State of Pennsylvania, have invented certain new anduseful Improvements in Adding and Subtracting Devices, of which thefollowing is a specification.

This invention relates to adding and subtracting machines, and moreparticularly to such machines of the type called vest pocket size.

One of the main objects is to provide a device especially adapted foradding or subtracting inches and fractional parts thereof. Anotherobject is to provide such a device of very reduced volume and easyoperation. A further object is to provide a machine of very simple andcheap manufacture. Further objects and advantages will appear from thedetailed description and the drawings forming a part of thisapplication.

In the drawings:

Fig. 1 is a front elevation showing the distinctive features of myinvention.

Fig. 2 is a cross-sectional View taken.

along the line 2-2 in Fig. 1. 1

Fig. 3 shows a modified graduation used on my invention.

Referring more in detail to Figs 1 and 2, my invention consists of thestationary graduated disc 1 centrally perforated to receive thecylindrical brass sleeve or eyelet 2 upon which are rotatably andcentrally mounted the discs 3 and 4 situated respectively at the frontand the rear of the main disc. Suitable spacing washers 5 and 6 areinserted betweenthe discs to reduce the frictional wear and insureproper rotation of the outer discs.

A hand 7 is rotatably mounted on the eyelet 2 outwardly of the disc 3and is separated therefrom by the small washer 8. This hand is providedwith the securely mounted grip-knob 9 and the pin 10 directed inwardlyof the hand to engage the holes 11 spaced uniformly andcircumferentially on the disc 3.v

As shown in Fig. 2, the ends of the eyelet 2 are turned over to provideflanges 12 for retaining the outer discs 3 and 4.

In Fig. 1 I have shown my adding machine adapted for adding inches andfractions thereof, down to one-sixty-fourths. With this end in view, thecircumference of the main disc 1 is-evenly divided into 64 partsseparated by the radial lines 13. The Be it known that I, ALBERTWOLPERT, a

annular space situated between the main disc and the rotating disc 3 isdivided into three rings by the two concentric circles 14 and 15 which,in conjunction with the radial lines 13, divide this space into theringsectors 16 designed to contain the various figures. Referring toFig. 1, it will be noted tha in the outer ring I indicate the numeratorsand in the middle ring the denominators of the fractions. The graduationin the outer ring is made in clock-wise direction, the variation betweeneach division being one sixty-fourth, and all fractions being reduced totheir smallest denominator. The graduation in the inner ring refers alsoto the numerators, but it is run in the opposite direction to that shownin the outer ring. Due to this arrangement, it will be observed that thefigures in the outer ring form the complement of those indicated in theinner ring, that is, the sum of the outer and inner figures for a givendivision will e ual the denominational number shown in t e middlesector.

To facilitate the reading of the graduations, I generally accentuate thedivision lines enclosing'the fractions most in use, as shown in Figure 1for the fractions one quarter, one half, three quarters and the unit.Also, I provide on the rotating disc 3 the triangular arrow-point 17which serves as an indicator or starting indicia for the operation of mydevice.

The operation of my device is very simple and can best be illustrated bythe succeeding examples.

To add the following fractions of an inch: 1/4, 7/16, 9/32, and 15/64",proceed in this manner:

Place the arrow-point 17 at 0; turn hand 7 counter-clock-wise and placethe pin 10 into the hole in the disc 3 opposite to 1/4 in the innerrings; turn hand 7 and disc 3 clockwise into the position opposite to 0and repeat the same operations for the other fractions. The total sumwill be one and thirteen sixty fourths;the fraction being read in theouter rings and the digit being obtained by counting the number of timesthe arrow-point 17 passes the zero point.

For the pur ose of expediting the setting of the hand into the zeroposition, the stationary disc 1 is provided at this point with a hole,coinciding with the perforations 11 in the disc 3, which acts as a stopfor the pin 10.

To subtract 25/64: and 13/32 from 1",

for example, set arrow-point 17 at zero, turn hand counter-clock-wiseinto the hole opposite to 25/64", inner rings, and move the rings.

In Figure 3 I have shown an adaptation of my device for use with wholenumbers, up to one hundred. As will be seen, the graduation in the outerand inner rings run in opposite directions and the intermediate ring isleft blank since it is only intended for denominators.

The operations for this modifiedform of my invention are carried in ananalogous manner as described for the fractions and need therefore notbe explained again.

To increase the usefulness of my invention, I avail myself of the emptyspaces to print valuable information for the various trades. Thus, forexample, I provide in the disc 3, Figure 1, an opening 18, which enablesthe user of my device to obtain the decimal equivalent of any givenfraction by turning the disc until the arrow points to said fraction andreading the equivalent, printed on the stationary disc and beneath therotating disc, as indicated by the ,cut 19, through the opening 18.

The object of the rotating disc 4, is to provide further suchinformation as may be valuable for the various trades for which mydevice may be made purposely.

If desired, my adding machine may be arranged for fractional and wholenumbers by placing on one side of the stationary disc the graduationsshown on Figure 1 and on the other side the graduations and rotatingdisc shown in Figure 3 and supplying each side with a hand 7.

It may be found desirable in practice to resort to slight changes inconstruction and arrangement of the details of my invention withoutdeparting from the field and scope of the same, and I intend to includeall such variations, as fall within the scope of the appended claim, inapplication in which the preferred forms only of my invention aredisclosed.

What I claim is:

In a device for adding inches and fractions thereof, the combination ofastationary' disc; a second disc of lesser diameter centrally androtatably mounted thereon; the annular space provided between theperipheries of said discs being divided into three concentric spaces andcircumferentially into as many ring-sectors as correspond to thedenominator of the smallestfraction of an inch for which the device canbe used; the ring-sectors in the outer and inner rings bearing thenumerators of the various fractions; the numerators in the outer ringprogressing arit-hmetically in opposite direction to those of the innerring; the ring-sectors of the intermediate ring bearing the denominatorof the fractions;

a plurality of apertures provided circum- 7b ferentially on saidrotatable disc; said apertures corresponding in number and radialalignment with the ring-sectors; a hand rotatably mounted on the commoncenter of said disc; said hand being provided with a pin securelymounted thereon for selective engagement with the circumferentiallydisposed apertures provided in said rotatable disc.

In testimony whereof I afiix my signature.

ALBERT WOLPERT.

